首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   41700篇
  免费   1689篇
  国内免费   22篇
  2020年   429篇
  2019年   477篇
  2018年   765篇
  2017年   729篇
  2016年   771篇
  2015年   539篇
  2014年   689篇
  2013年   3187篇
  2012年   1180篇
  2011年   1273篇
  2010年   720篇
  2009年   777篇
  2008年   1044篇
  2007年   1105篇
  2006年   982篇
  2005年   898篇
  2004年   839篇
  2003年   817篇
  2002年   823篇
  2001年   1433篇
  2000年   1375篇
  1999年   1052篇
  1998年   439篇
  1997年   395篇
  1996年   400篇
  1992年   873篇
  1991年   826篇
  1990年   846篇
  1989年   760篇
  1988年   763篇
  1987年   706篇
  1986年   739篇
  1985年   788篇
  1984年   622篇
  1983年   541篇
  1982年   410篇
  1981年   387篇
  1979年   655篇
  1978年   495篇
  1977年   405篇
  1975年   551篇
  1974年   685篇
  1973年   695篇
  1972年   545篇
  1971年   507篇
  1970年   464篇
  1969年   461篇
  1968年   610篇
  1967年   539篇
  1966年   535篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
There is substantial evidence of detrimental psychological sequelae following disasters, including terrorist attacks. The effect of these events on extreme responses such as suicide, however, is unclear. We tested competing hypotheses about such effects by employing autoregressive integrated moving average techniques to model the impact of September 11 and the Oklahoma City bombing on monthly suicide counts at the local, state, and national level. Unlike prior studies that provided conflicting evidence, rigorous time series techniques revealed no support for an increase or decrease in suicides following these events. We conclude that while terrorist attacks produce subsequent psychological morbidity and may affect self and collective efficacy well beyond their immediate impact, these effects are not strong enough to influence levels of suicide mortality.  相似文献   
22.
When some pictures are mirror reversed, aesthetic evaluations of them change dramatically. Stimulus features that may be important in contributing to this effect are: (a) location of areas of principal interest or weight in the picture space, (b) cues that suggest a direction of motion within the picture. Dextrals and inverted sinistrals preferred paintings with cues suggesting motion proceeding from left to right over their mirror-reversed versions and also preferred those with weight concentrated in the left portions of the picture space. The explanation that best fits these data is that preference is promoted when the picture content encourages attention to its rightmost portions, thus placing a majority of the picture in the left visual field where it is directly processed by the right hemisphere.  相似文献   
23.
This study examined the influence of various group diversity dimensions on collaborative creativity related to the healthcare system. Research findings on the association between diversity and brainstorming performance has been mixed. Diversity that increases cognitive stimulation or promotes elaboration has been shown to increase group performance. Participants exchanged ideas, replied, and elaborated using an electronic discussion board in an asynchronous fashion in groups of five over a period of 4 weeks. The groups varied in diversity of ethnicity, gender, age, and political orientation, but participants were not made aware of this diversity. Age and gender diversity were related to lower levels of replying to ideas and lower idea novelty but political diversity was related to increased replies and novelty. If a topic engages people with different perspectives to actively respond to others’ ideas, this can increase the creative potential of idea sharing in groups. Political or value-based diversity has the potential for creative solutions if the other participants’ political or value-based identities are not made salient.  相似文献   
24.
Evaluated the effect of varied physician affect on subject recall, anxiety, and perceptions in a simulated tense and ambiguous medical situation. Forty women at risk for breast cancer viewed videotapes of an oncologist presenting--with either worried or nonworried affect--mammogram results. Although the mammogram results and the oncologist were the same in both presentation, analyses indicated that, compared to the women receiving the results from a nonworried physician, the women receiving the results from a worried physician recalled significantly less information, perceived the clinical situation as significantly more severe, reported significantly higher levels of state anxiety, and had significantly higher pulse rates. These results suggest that physician affect plays a critical role in patient reaction to medical information. Implications for compliance research, patient satisfaction, and physician training are discussed.  相似文献   
25.
Convergent and divergent stereo mechanisms were compared in their ability to recover structure from motion. Contrary to a recent result reported by Richards and Lieberman, no difference in their performance was found; both mechanisms appeared equally capable of supporting the perception of good structure from motion. Possible reasons for the disparate results are discussed.  相似文献   
26.
27.
28.
29.
30.
P Bressan 《Perception》1987,16(5):671-675
If a few parallel horizontal rows of dots are set diagonally, like steps, across the visual field, the inner rows appear not to be horizontal but sloping up to one side; the effect holds as long as the vertical distances between the rows do not exceed a given visual angle. This illusion, described by Vicario in 1978, was never explained. An experiment is reported in which the illusion was still visible at row separations well in excess of the spatial limits originally considered, provided the stimulus elements were enlarged. The maximum illusion was obtained for length ratios (interrow distance to size of dots) identical to those which have been shown to produce the largest effects in a number of illusions of area and length. This suggests that Vicario's illusion is similar to other illusions of extent, and that it can be explained by a neural extent-coding model.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号